Directional drilling is generally accomplished by putting a bend and stabilizers in the drillstring, which will allow the orientation of the drillbit and, therefore, the change of wellbore orientation. Bend connections can be of the fixed type for a particular angle. These bend connections are assembled at the surface into the drillstring and run in the wellbore and the bit is rotated by a motor so that the deviation is achieved. The bend can be created from the surface if elaborate controls and actuating mechanisms are provided so that a signal from the surface actuates movement downhole to create the bend as desired. Typical of such devices are U.S. Pat. Nos. 5,441,119; 4,374,547; 5,503,235; 5,117,927; and 5,311,952. Some designs depend on rotation to the left to create a bend connection. This design is illustrated in U.S. Pat. No. 4,694,914. Other designs involve external wedges which are used to predetermine the angle of the bend. Such a design is illustrated in U.S. Pat. No. 5,314,032. Other designs allow the creation of a variety of angles, with an internal bolt to secure the angle selected, coupled with an external thread to connect the two components which are used to create the bend. Typical of such a design is U.S. Pat. No. 4,077,657. This is not a design which is usable between a power section and a bearing section of a downhole motor which has a driveline through it. It is advantageous to place the bend connection close to the bit. Designs, such as shown in U.S. Pat. No. 4,077,657, is used in the area of drill collars which are uphole from the downhole motor.
It is desirable to put the bend connection as close to the bit as possible, and the preferred location is generally between the power section of the mud motor, which can be a progressive cavity-type of a motor, also known as Moineau, and the bit. One of the situations that occurs when drilling with a mud motor is that the bit, which is normally driven by the mud motor to the right, will wear out and develop an undersized OD. Therefore, the hole size will be reduced and the lower motor housing can become stuck. When such conditions occur, if the string is released at the rotary table at the surface, accumulated torsion in the drillstring will be released so that a reverse rotation to the left occurs. If the string is picked up at the surface, the bit is released and it rotates to the right and passes a neutral position, which results in a subsequent rotation to the left. Threaded joints in the area of the bend connection of the mud motor can, as a result of this reverse rotation to the left, become undone. These joints are typically the connections with the lowest make-up torque in the whole drillstring and therefore have the lowest resistance to reverse rotation to the left. Accordingly, for bend connections which are disposed between the power section of the downhole mud motor and the bit, it is desirable to be able to select the desired angle and put the bend connection together in such a way that it will not be subjected to becoming disconnected upon reverse rotation of the drilistring, which could result in dropping the bit and the lower parts of the motor in the wellbore. Thus, the object of the invention is to provide a simple design for manual selection at the surface of the predetermined angle which will be employed for further drilling of the wellbore, while at the same time presenting a bend connection that can easily transmit torque, regardless of the angle which is selected. These and other desirable features of the invention will become apparent by a review of the enclosed drawings and the description of the preferred embodiment.